1. Field of the Invention
This invention relates in general to devices for lawn and yard care, and more particularly to a carriage which may be attached to a weed trimmer for converting the trimmer to a lawn mower.
2. Description of the Prior Art
Motor driven lawn care devices generally fall into two categories. The first type of device is the conventional lawn mower, which is a wheel-mounted machine having rotary blades for cutting grass and the like. Lawn mowers are ideal for cutting large expanses of grass in relatively flat, unobstructed areas, because the wheeled carriages allow the operator to move quickly and easily over long distances. However, conventional mowers are not suitable for removing vegetation from around walls, fences, trees, flower beds, and other similar locations because the bulky carriage tends to get in the way, and because the weight of the mower makes it difficult to tilt the device at the angles necessary for efficient edging and scalping. In addition, conventional lawn mowers are expensive to purchase and to maintain, cumbersome to store, noisy, and unpleasant-smelling because of the fuel used to power the engine. These inconveniences may seem minor to property owners having average or large-sized lawns, but to residents or caretakers of apartment complexes, trailer parks, and high-density housing developments with small lawns, the disadvantages of conventional lawnmowers may outweight the benefits.
The second type of motor-driven lawn care device is the weed trimmer. A typical weed trimmer utilizes flexible, non-metallic monofilament cutting line which is rotated at high speeds by a motor output to cut weeds or grass in places that a conventional mower cannot reach. Typically, the motor is enclosed in a housing which includes a protective shield above the cutting line, and is provided with an elongated pole handle for hand-carrying the device. Many property owners, not willing to invest in a large lawnmower for the reasons given above, purchase this type of weed trimmer for mowing their small yards. However, they quickly find that hand-carrying the device is fatiguing due to the weight of the motor. In addition, on certain landscapes, such as hills, the trimmer can be dangerous since they tend to upset the operator's balance.
In order to solve the problems associated with both lawn mowers and weed trimmers, attempts have been made to provide carriages on which trimmers may be removably mounted to convert the trimmers into lawn mowers. These attempts are disclosed in U.S. Pat. Nos. 4,287,709, 4,343,139 and 4,389,836 to Lowry et al.
Each of the carriages disclosed by Lowry et al comprises an enlarged wheeled platform which is provided with a centrally located aperture for receiving the lower portion of the weed trimmer housing. The motor housing, including the protective shield for the cutting line extends above the platform, while the cutting line itself extends below the platform. Rigid coupling means are provided on the platform and on the housing for securely attaching the trimmer to the carriage.
The carriages disclosed by Lowry et al suffer from a number of drawbacks. One problem is that the enlarged platform, which extends well beyond the area of the motor housing, makes it impossible for the trimmer to be used very close to obstructions such as posts or edges of paths and driveways. Also, the pole handle attached to the motor housing is insufficient to move such a large carriage; thus, it is necessary to provide the carriage with a handle of its own. Another problem is that, because the trimmer is supported with its line shield above the platform of the carriage, the operator is unable to take advantage of the automatic line-adjusting feature with which certain popular models of weed trimmers are equipped. This feature, which is marketed under the trade name "Tap-N-Go", enables the operator to automatically advance up to 3 inches of cutting line simply by lightly tapping the cutting head on the ground. However, the carriage disclosed by Lowry et al prevents the head from contacting the ground unless the operator removes the trimmer from the carriage. In addition, the rigid mounting of the trimmer on the carriage prevents the operator from tilting the cutting head to any position other than exactly parallel to the ground, while still maintaining all four wheels of the carriage on the ground. This hinders the performance of the trimmer, since it has been determined that optimum performance is obtained when the front end of the trimmer is actually tilted from 2.degree. to 4.degree. downwardly from parallel with respect to the ground.
Therefore, a need exits for a new and improved weed-trimmer-to-lawn-mower conversion carriage which overcomes some of the problems and shortcomings of the prior art.